Historically, flexible bulk containers have been used for receiving, storing, transporting and discharging flowable materials of all types. The containers are typically constructed in a square, vertically rectangular or circular shape with lift straps attached to each of the uppermost corners of the square, rectangle or circle.
By way of example, the flexible bulk containers are used for handling granular, liquid or powder (flowable) materials such as chemicals, minerals, fertilizers, foodstuffs, grains and agricultural products. The advantages of such receptacles include relatively low weight, reduced cost, versatility and, in the case of reusable receptacles, low return freight costs.
At the present time most flexible bulk containers are manufactured from woven polypropylene fabric. Typically, such containers are constructed by stitching or sewing together two or more sidewalls and a bottom portion. Optionally, a top portion, lift straps or other structural support can be added to this basic construction. The traditional method of securing the seams of the several portions of the container includes sewing or stitching, a time-consuming, labor-intensive and therefore expensive process. Usually, attachment of the bottom portion to the remaining piece or pieces, a critical step in the manufacture of a container, consumes the most time, labor and expense. Thus a need has arisen for a method of construction of a container wherein the bottom panel is quickly, easily and inexpensively attached to the container.
Furthermore, needle holes created in the stitching process allow powdered materials to sift through the holes. Thus a need has arisen for a method of construction of a container that does not use conventional stitching for the bottom seams.